They probably use an electrified system with wiring and servos, levers and push rods. Prior to that we used hydraulics. These parts are probably accessible with removable panels.
If they had, they'd still have mechanical pivots and so forth that can wear, but the article specifically mentions pulleys and cables:
> The team also inspected flight control pulleys and cables, which are routed through the wings to the systems bay, as well as the aileron trays on the outboard portion of each wing. (Ailerons are the hinged part of each wing that control roll or maneuvers, and are controlled by the pilot via wire pulleys that run through the wings.)
I suppose that the cables have to run out of the wings and into the cockpit in order to be useful, and that you could put you adjustments for cable stretch, etc in a place you could get to them easily. Or add access panels, as you suggest.
